JPH0367473A - Inspection method for sealed lead-acid battery - Google Patents

Abstract

PURPOSE:To detect the scratch and perforation of film surface, the separation of the fused part of a film, the electrification of an outer case and the like by applying voltage between the outer case and the terminal of a battery housed therein, and detecting continuity current or the extent of a voltage drop. CONSTITUTION:Voltage is applied between a terminal (a) and an outer case 1, and continuity current or a voltage drop is detected for making inspection. If a scratch, perforation or the like exists on the film surface of a sealed lead acid battery constitution cell 2, electric discharge takes place between the case 1 and a plate during the application of voltage and continuity current increases, thereby enabling inspection.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for testing sealed lead-acid batteries used in consumer portable appliances and the like.

Conventional technology Sealed lead-acid battery structure using a film for the exterior body Sealed lead-acid batteries, in which a single cell or multiple cells are housed in a conductive exterior case made of metal, are susceptible to scratches on the film surface during the process of housing the exterior case. In order to detect cells with poor airtightness due to holes, peeling of welds, etc., cells were aged after being stored in an outer case, and the oxidation state of the negative electrode plate was measured based on the charging characteristics after aging.

If a broken or leaking cell or a cell-to-cell connection comes into contact with the exterior case and the exterior case becomes electrically charged, there is a risk of short-circuiting and ignition or smoke when the battery is stored in the equipment in which it will be used.

As this inspection method, the voltage between the battery terminal and the outer case was measured.

Problems to be Solved by the Invention In the method described above, the rate of oxygen permeation through the scratches and holes is determined by the size of the scratches and holes on the film surface that occur during the process of storing the outer case, and the location where the scratches occur. There was a problem that negative electrode plates with small oxidation during aging were not detected. Charges on the outer case due to liquid leakage or contact between the connection between cells and the outer case were not detected during inspection. Although this is possible, there is a problem in that it cannot detect objects that are charged due to external factors such as vibration or dropping during actual use.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention applies a voltage between the battery terminal and the outer case after the outer case is stored,
By detecting the magnitude of the conduction current or voltage drop at that time, scratches on the film surface, holes, peeling of the welded part, charging of the outer case, etc. can be detected.

This improves the accuracy of detecting batteries with poor airtightness during the outer case storage process and charged batteries in the outer case, making it possible to supply highly reliable and safe sealed lead-acid batteries. Examples of the invention will be described.

In FIG. 1, a single sealed lead-acid battery 2 is housed in a conductive exterior case 1, with cells connected through connectors 4 and terminals 3. As shown in FIG. In the inspection method according to the present invention, a voltage is applied between the terminal 3 (the positive electrode or the negative electrode is not particularly important) and the outer case 1, and the conduction current or voltage drop at that time is detected and inspected. If there are scratches or holes on the film surface of the sealed lead-acid battery unit 2, the applied voltage will cause a discharge between the outer case 1 and the electrode plate when voltage is applied, resulting in a conduction current (or (voltage decreases), and inspection can be performed by detecting this.

Table 1 shows the correlation between the applied voltage and the detection accuracy of the method according to the present invention, and the comparison with the conventional method. The dielectric breakdown voltage of the film is 3 kV or more. A conduction current of 1 mA or more was defined as a defect criterion.

Holes in the low applied voltage range of 05kV to 1kV.

Small scratches are not detected. On the other hand, if the voltage is 2 kV or more, erroneous determinations will occur more often due to electric discharge between the connector 4 and the outer case 1.

The optimal applied voltage was 1.5 kV.

In the conventional method, the detection accuracy was 60% even after aging, but according to the present invention, the detection accuracy is improved to 100%.

According to this inspection method, it is also possible to detect charging and liquid leakage of the outer case 1.

At an applied voltage of 15 kVO, if the inter-electrode distance becomes less than oamm, a discharge occurs and it is determined to be defective. In other words, if this inspection method is carried out, the distance between the inter-cell connection part of the connector 4 and the outer case 1 is secured to be 0.8 mm or more, so vibrations and
The exterior case 1 is not electrically charged due to external factors such as dropping.

(Margins below) Table 1 Effects of the Invention As described above, according to the present invention, it is possible to accurately detect scratches, holes, and peeling of welded parts on the film surface during the process of storing batteries in the exterior case, and also to detect defects in the exterior case. It is also possible to detect batteries whose cases are electrically charged, batteries that may become electrically charged, and leaking cells, making it possible to supply sealed lead-acid batteries with higher reliability.

[Brief explanation of drawings]

FIG. 1 is an external view showing the method for testing a sealed lead-acid battery according to the present invention.

Claims (1)

[Claims] An electrode plate group consisting of positive and negative electrode plates and separators impregnated with an amount of electrolyte that will not be released is sandwiched between a film laminated with heat-fusible resin on the inner surface, and a synthetic resin frame surrounding the electrode plate group. Sealed lead-acid battery structure in which the above-mentioned film or the above-mentioned films are heat-welded to each other and sealed.In a sealed lead-acid battery in which a single cell or a plurality of cells with inter-cell connections are housed in a conductive exterior case, a sealed lead-acid battery is used. A method for inspecting a sealed lead-acid battery, characterized by applying voltage between the external terminal and the exterior case of the lead-acid battery, and detecting conduction current or voltage drop when voltage is applied.